Surface heat treatment can significantly improve the fatigue strength of workpieces

Surface heat treatment can significantly improve the fatigue strength of the workpiece:

Surface heat treatment can significantly improve the fatigue strength of the workpiece. For example, for the automotive half axle made of 40MnB steel, the original process was overall quenching and tempering, and it was changed to quenching and tempering+surface heat treatment, which increased the service life by nearly 20 times. In addition, surface heat treatment reduced the notch sensitivity of the parts. The size of the outer plate mold is generally large,

If a patchwork structure is used, there may be tensile damage at the joints, so most of them adopt an overall structure, and the materials generally use cast iron materials such as ductile iron. The hardness of the forming and feeding parts can reach around 50-55HRC after flame quenching. The surface treatment of the outer plate mold for the overall structure of Dalian metal surface treatment mostly adopts the hard chromium plating process

However, its surface hardening effect is limited, with a surface hardness of about 1000HV. In addition, the hard chromium plated coating is mechanically combined with the mold base material, which is prone to detachment when the forming pressure is high. Once the coating is detached, its tensile resistance will also be lost. When the surface hardening layer is worn, galling will occur again.

This technology can be used for molds with low requirements. The wear resistance and fatigue wear resistance of surface heat treatment parts under dry friction sliding wear conditions are higher than those of ordinary heat treatment parts, which is due to the comprehensive results of fine martensite grains in its structure, high carbide dispersion and relatively high pressure stress on the surface.

It has excellent wear resistance, self-lubrication, anti bite, high-temperature oxidation resistance, and corrosion resistance, which can improve the service life of molds several times or even 10 times, and has received high praise in the mold industry.